1. Field of the Invention
The present invention relates to a manipulator system having a manipulator and a controller, as well as to a control apparatus for controlling a manipulator or the like. In particular, the present invention relates to a manipulator system and a control apparatus, wherein a portion or the entirety of the manipulator is structured so as to be detachable with respect to the controller.
2. Description of the Related Art
In laparoscopic surgery, a number of small holes are opened in a patient's abdomen or the like, and an endoscope, a manipulator (or forceps), or the like is inserted, and surgery is carried out while the surgeon observes an image from the endoscope on a monitor. In this type of laparoscopic surgery, owing to the fact that opening of the abdominal cavity is unnecessary, the burden on the patient is small, and number of days required for the post-operative recovery and number of days spent in the hospital can be significantly reduced. Therefore, laparoscopic surgical operations are expected to find an increased range of applications.
A manipulator system, for example, as disclosed in Japanese Laid-Open Patent Publication No. 2004-105451, comprises a manipulator main body, and a control apparatus for controlling the main body. The manipulator main body comprises an operation command unit and a working unit, which is detachable and exchangeable with respect to the operation command unit.
The working unit includes an elongate connecting shaft, and an end operator (referred to as an “end effector”) disposed at the end of the connecting shaft. One or more motors are disposed in the operation command unit for driving the working unit at the distal end by means of wires. The wires are trained around pulleys at a proximal end side. The control apparatus drives the motors and also drives the wires in a circulatory manner via the pulleys.
Because of the necessity to easily clean and disinfect the working unit periodically, the working unit does not contain any electronic components such as sensors or the like, and the positions and origin points of the end effector and the base end pulleys cannot be detected directly. Rather, a structure is provided in which the posture of the end effector is calculated based on a rotation amount of the motors.
Incidentally, in laparoscopic surgery, various different types of working units are used depending on the surgery involved. A gripper, a cutter, an electrical knife, an ultrasonic knife, a surgical drill, or the like may be given as examples thereof. Such working units are disposed detachably with respect to the operation command unit, and when installed, the pulleys on the proximal end side of the working unit engage with rotary axes of the motors disposed in the operation command unit.
In this manner, in the case of a system, which is predicated on enabling the connection of multiple different types of working units with respect to a single operation command unit, it is necessary to set the motor phases such that all of the working units acquire a sole common posture enabling attachment and detachment thereof (see, e.g., Japanese Laid Open Patent Publication No. 2004-105451). Such a posture is referred to as an origin posture (or an initial posture).
Further, when it is desired to exchange the end effector with another type, it is advisable also to exchange the manipulator main body. In this case, a connector, which connects the control apparatus and the operating unit of the manipulator main body, is disconnected, and another connector of a different manipulator main body is reconnected.
With general manipulators available in the industry, although the manipulator and control apparatus are not detached (cut off) while the system is in use (during system operation), it is preferable for detachment (cutting off) between the manipulator and the control apparatus to be easily carried out, since as indicated above, multiple different types of working units are utilized with the manipulator.
In this manner, in the event that the manipulator is to be exchanged with another unit, when the connector is reconnected, generally it is required that the power supply to the control apparatus be switched OFF, and then the connector is detached. This is because, in the operation command unit, an encoder for detecting the angle of rotation of the motors is provided, wherein the circuit for driving the motors is constructed in a closed loop together with the control apparatus, and therefore an open loop condition can happen (referred to below simply as “open loop”), in which motor rotations may occur not as intended, as a result of cutting off the output signal from the encoder midstream.
More specifically, in the connector that interconnects the control apparatus and the manipulator, pins for two motor wires (M+, M−) and four encoder wires (A-phase, B-phase, circuit power source Vcc, Gnd) are provided, and to prevent the occurrence of an open loop, it is necessary that all of these pins be detachable simultaneously, or that the power wires to the motor be cut off before the encoder wires. However, in actual practice, when a connector having a large number of pins is disconnected, not all of the pins can be disconnected at the same time, and an open loop occurs momentarily. Accordingly, when detachment of the aforementioned connector is carried out, it is still required to turn off the power supply of the control apparatus beforehand.
The following may be cited as conventional techniques concerning manipulator systems: Japanese Laid Open Patent Publication No. 2004-105451, Japanese Laid Open Patent Publication No. 2004-208922, and U.S. Pat. No. 6,331,181.
Japanese Laid Open Patent Publication No. 2004-105451 proposes a structure in which it is unnecessary to consider switching of the motor excitation or electrical configurations at the time of detachment.
Japanese Laid Open Patent Publication No. 2004-208922 discloses features related to electrical detachment of plural end tools (working units).
According to U.S. Pat. No. 6,331,181, in relation to attachment and detachment of a medical manipulator, a circuit is included in a front-end manipulator for extracting an ID, wherein controls are carried out by the control apparatus based on obtaining such information.
Incidentally, as described above, the posture of the end effector is calculated taking as a standard the origin position thereof, for example. Accordingly, in the case that the working unit is exchanged during an operation, it is essential for the posture of the newly installed and different working unit to match with the origin position accurately. Stated otherwise, when the working unit is separated from the operation command unit, it is desirable that the working unit be placed in a posture that matches with the origin position thereof.
For this purpose, and so that the working unit cannot be detached except when in its origin position, a method is conceivable, made up of a system that applies a mechanical interlock. However, with such a method, fixing and releasing of the interlock mechanism with each restoration of the origin position must be carried out repeatedly a large number of times, thus making the method complex.
On the other hand, a method may be conceived of by which individual identifying information from each of the working units is obtained, and the motor angles are stored by the control apparatus at a point in time when the units are detached. Then, the next time that a medical device is attached to the control apparatus, but before initiating operation thereof, processing is performed to set the motor phases automatically. However, with this method, the operation command unit is connected to the control apparatus, and by connecting the operation command unit and the working unit, distinct identifying signal lines are connected to the control apparatus. Because IDs are first capable of being acquired at this time, if at the time of connection the motor phases are shifted and a connection cannot be established, the individual information cannot be recognized.
Further, in the event it is desired to exchange the end effector, when the connector is reconnected, generally speaking, the power supply to the control apparatus is turned OFF as discussed previously. However, when the power supply is turned OFF, the connector is detached, and thereafter the power supply to the control apparatus is turned ON again, the computer system inside the control apparatus is reinitiated, so that a certain amount of time is required for rebooting.
Moreover, in Japanese Laid Open Patent Publication No. 2004-105451, no disclosure is provided concerning attachment and detachment of a connector between a manipulator main body and a control apparatus.
In Japanese Laid Open Patent Publication No. 2004-208922, since a closed loop does not exist within the motor control, a device is attached and detached for which changeover of the motor excitation is unnecessary. Although a manipulator is disclosed in the embodiments, the part that is actually attached and detached is simply a tool that is attached to the end of the manipulator. Attachment and detachment of the manipulator itself are not disclosed.
In U.S. Pat. No. 6,331,181, no disclosure is provided with respect to handling when a connector is attached and detached between the manipulator main body and a control apparatus.